Exposure of cherry radish (Raphanus sativus L. var. Radculus Pers) to iron-based nanoparticles enhances its nutritional quality by trigging the essential elements.

Iron (Fe) deficiency is a pervasive nutritional disorder, and producing vegetables enriched with Fe as a dietary source is imperative. Herein, Fe3O4, FeO(OH), α-Fe2O3, ß-Fe2O3, γ-Fe3O4, and nZVI nanoparticles (NPs) were applied in soil as fertilizer to enhance the Fe nutrition in cherry radish. The highest enhancement of Fe content (58%) was observed in Fe3O4 treatment at 100 mg kg-1, followed by FeO(OH) (49%), α-Fe2O3 (24%), nZVI (14%), ß-Fe2O3 (13%) and γ-Fe3O4 (4%). The daily intake of Fe was 97-104% and 77-91% with Fe3O4 and FeO(OH) at 100-200 mg kg-1, respectively. Moreover, the zinc, vitamin C and crude protein contents were also increased by 37, 48 and 67% under Fe3O4 treatment as compared to control. Fe3O4 at 100 mg kg-1 also increased the essential amino acids (phenylalanine, leucine and isoleucine) contents by 11-14%. These data suggest that Fe3O4 and FeO(OH) NPs could be effective nanofertilizers to enhance Fe nutrition in plants.

Stress signaling convergence and nutrient crosstalk determine zinc-mediated amelioration against cadmium toxicity in rice.

Consumption of rice (Oryza sativa L.) is one of the major pathways for heavy metal bioaccumulation in humans over time. Understanding the molecular responses of rice to heavy metal contamination in agriculture is useful for eco-toxicological assessment of cadmium (Cd) and its interaction with zinc (Zn). In certain crops, the impacts of Cd stress or Zn nutrition on the biophysical chemistry and gene expression have been widely investigated, but their molecular interactions at transcriptomic level, particularly in rice roots, are still elusive. Here, hydroponic investigations were carried out with two rice genotypes (Yinni-801 and Heizhan-43), varying in Cd contents in plant tissues to determine their transcriptomic responses upon Cd15 (15 µM) and Cd15+Zn50 (50 µM) treatments. High throughput RNA-sequencing analysis confirmed that 496 and 2407 DEGs were significantly affected by Cd15 and Cd15+Zn50, respectively, among which 1016 DEGs were commonly induced in both genotypes. Multitude of DEGs fell under the category of protein kinases, such as calmodulin (CaM) and calcineurin B-like protein-interacting protein kinases (CBL), indicating a dynamic shift in hormonal signal transduction and Ca2+ involvement with the onset of treatments. Both genotypes expressed a mutual regulation of transcription factors (TFs) such as WRKY, MYB, NAM, AP2, bHLH and ZFP families under both treatments, whereas genes econding ABC transporters (ABCs), high affinity K+ transporters (HAKs) and Glutathione-S-transferases (GSTs), were highly up-regulated under Cd15+Zn50 in both genotypes. Zinc addition triggered more signaling cascades and detoxification related genes in regulation of immunity along with the suppression of Cd-induced DEGs and restriction of Cd uptake. Conclusively, the effective integration of breeding techniques with candidate genes identified in this study as well as economically and technologically viable methods, such as Zn nutrient management, could pave the way for selecting cultivars with promising agronomic qualities and reduced Cd for sustainable rice production.

Zinc alleviates cadmium toxicity by modulating photosynthesis, ROS homeostasis, and cation flux kinetics in rice.

Understanding of cadmium (Cd) uptake mechanism and development of lower Cd crop genotypes are crucial for combating its phytotoxicity and meeting 70% increase in food demand by 2050. Bio-accumulation of Cd continuously challenges quality of life specifically in regions without adequate environmental planning. Here, we investigated the mechanisms operating in Cd tolerance of two rice genotypes (Heizhan-43 and Yinni-801). Damage to chlorophyll contents and PSII, histochemical staining and quantification of reactive oxygen species (ROS), cell viability and osmolyte accumulation were studied to decipher the interactions between Cd and zinc (Zn) by applying two Cd and two Zn levels (alone as well as combined). Cd2+ and Ca2+ fluxes were also measured by employing sole Cd100 (100 µmol L-1) and Zn50 (50 µmol L-1), and their combination with microelectrode ion flux estimation (MIFE) technique. Cd toxicity substantially reduced chlorophyll contents and maximal photochemical efficiency (Fv/Fm) compared to control plants. Zn supplementation reverted the Cd-induced toxicity by augmenting osmoprotectants and interfering with ROS homeostasis under combined treatments, particularly in Yinni-801 genotype. Fluorescence microscopy indicated a unique pattern of live and dead root cells, depicting more damage with Cd10, Cd15 and Cd15+Zn50. Our results confer that Cd2+ impairs the uptake of Ca2+ whereas, Zn not only competes with Cd2+ but also Ca2+, thereby modifying ion homeostasis in rice plants. This study suggests that exogenous application of Zn is beneficial for rice plants in ameliorating Cd toxicity in a genotype and dose dependent manner by minimizing ROS generation and suppressing collective oxidative damage. The observations confer that Yinni-801 performed better than Heizhan-43 genotype mainly under combined Zn treatments with low-Cd, presenting Zn fortification as a solution to increase rice production.

Cadmium-zinc cross-talk delineates toxicity tolerance in rice via differential genes expression and physiological / ultrastructural adjustments.

Understanding the physiological and molecular response of crop genotypes could be useful in eco-toxicological evaluation with cadmium (Cd) and could be a strategy to solve heavy metal contamination in agriculture. This study corroborates unique patterns of Cd accumulation and molecular mechanisms adopted by plants to acquire Cd tolerance and counteractive effects of zinc (Zn) against Cd toxicity. Two rice (Oryza sativa) genotypes (Heizhan 43 and Yinni 801) differing in cadmium tolerance and its accumulation in plant tissues were investigated hydroponically using two Cd levels [Cd10 (10 µM L-1) and Cd15 (15 µM L-1)] and two Zn levels [Zn25 (25 µM L-2) and Zn50 (50 µM L-1)] and their combinations. Cadmium toxicity rendered substantial reduction in plant height, biomass, chlorophyll contents and photosynthesis as compared to the control plants after 15 days of treatment. Supplementation of Zn evidently ameliorated Cd toxicity by minimizing the reduction in plant growth, chlorophyll contents and photosynthetic attributes (Pn, gs, Ci, and Tr). Comparatively, lower accumulation of Cd in Yinni 801 under combined treatments revealed a preferential uptake of Zn in this genotype. A cross-talk among Cd, Zn, Fe, Ca and K correlated with fluctuating gs, Ci and Tr. Both genotypes also differed in morphological alterations of cell membrane, chloroplasts and appearance of enlarged plastoglobuli along with distorted mitochondria. An increased ascorbate peroxidase activity in roots of Yinni 801 presented a defensive strategy. Relative expression of Cd and Zn ion transporter genes also confirmed the genotypic background of phenotypic divergence. The OsLCT1 and OsHMA2 expression was significant in Heizhan 43, indicating possible translocation of Cd from shoot to grains contrary to Yinni 801, which accumulated Cd in shoot and showed stunted growth. Zn supplementation promises tolerance to Cd in Yinni 801 by differential expression of putative genes for Cd translocation with minimum ultrastructural modifications by maintaining physiological functions in contrast to Heizhan 43.

Exposure to nickel oxide nanoparticles insinuates physiological, ultrastructural and oxidative damage: A life cycle study on Eisenia fetida.

Although, health and environmental hazards of Ni are ironclad; however, that of Nickle oxide nanoparticles (NiO-NPs) are still obscure. Therefore, impact of NiO-NPs exposure (0, 5, 50, 200, 500 and 1000 mg kg-1 soil) on the earthworm (Eisenia fetida) survival (at 28th day), reproduction (at 56th day), histopathology, ultrastructures, antioxidant enzymes and oxidative DNA damage was appraised in full life cycle study. Lower concentrations of NiO-NPs (5, 50 and 200) did not influence the survival, reproduction and growth rate of adult worms significantly. However, reproduction reduced by 40-50% with 500 and 1000 mg kg-1 exposure, which also induced oxidative stress leading to DNA damage in earthworms. Ultrastructural observation and histology of earthworms exposed to higher NiO-NPs concentrations revealed abnormalities in epithelium layer, microvilli and mitochondria with underlying pathologies of epidermis and muscles, as well as adverse effects on the gut barrier. To the best of our knowledge, this is the first study unveiling the adverse effects of NiO-NPs on a soil invertebrate (Eisenia fetida). Our findings clue towards looking extensively into the risks of NiO-NPs on soil organisms bearing agricultural and environmental significance.

The Nano-Magnetic Dancing of Bacteria Hand-in-Hand with Oxygen

ABSTRACT Magnetotactic bacteria are mostly microaerophilic found at the interface between oxic-anoxic zones. We report a magnetotactic bacterial strain isolated from an oil refinery sludge sample that grows aerobically in simple chemical growth medium, 9K. They open a new window of isolation of magnetic nanoparticles through an easy natural living system.

Effects of Curcuma longa extracts on mortality and fecundity of Bactrocera zonata (Diptera: Tephritidae) / Efeitos dos extratos de Curcuma longa sobre mortalidade e fecundidade de Bactrocera zonata (Diptera: Tephritidae)

The peach fruit fly, Bactrocera zonata, is a significant pest of fruit and vegetable crops in South East Asia and Pacific region. Ccontrol strategies of fruit flies, relying chiefly on insecticides, have serious environmental consequences, disturbing the agro-ecosystem as well as eliminating natural enemies. This study was oriented at exploring the potential of turmeric, Curcuma longa, extracts to control the peach fruit fly. Freshly emerged female adults of Bactrocera zonata were continuously fed for 16 days on diet containing 1000, 500 and 250 ppm of acetone extract of Curcuma longa separately in laboratory cages. The extract caused 85.00, 66.67 and 56.67 percent mortality at 1000, 500 and 250 ppm respectively. The surviving females were mated and allowed to reproduce on clean guava fruits in separate cages. The inhibition in pupal progeny was 67.90, 60.74 and 51.96 percent in the flies fed on 1000, 500 and 250 ppm, the inhibition observed in adult progeny was 84.68, 79.03 and 67.74 percent, respectively.

A mosca do pêssego, Bactrocera zonata, é uma importante praga das frutas e produtos hortícolas no Sudeste Asiático e Pacífico. As estratégias de controle de moscas-das-frutas, que se baseia principalmente no uso de inseticidas, têm consequências ambientais graves, perturbando o agroecossistema, bem como eliminando os inimigos naturais. Este estudo foi orientado a explorar as potencialidades dos extratos de açafrão Curcuma longa para controle de B. zonata. Após a emergência, adultos de fêmeas de B. zonata foram continuamente alimentados, durante 16 dias, com dieta contendo 1000, 500 e 250 ppm de extrato acetônico de C. longa separadamente em gaiolas no laboratório. O extrato causou 85,00, 66,67 e 56,67 por cento de mortalidade em 1000, 500 e 250 ppm, respectivamente. As fêmeas foram acasaladas e postas para ovipositar separadamente em goiabas dentro das gaiolas. A inibição na progênie pupal foi 67,90, 60,74 e 51,96 por cento nos insetos alimentados em 1000, 500 e 250 ppm, a inibição observada na progênie adulta foi 84,68, 79,03 e 67,74 por cento, respectivamente.

Calcium invigorates the cadmium-stressed Brassica napus L. plants by strengthening their photosynthetic system.

INTRODUCTION: Cadmium (Cd) in plants interrupts numerous metabolic processes and reduces the water and nutrient uptake that cause chlorosis, growth retardation, and ultimately plant death. Response of Brassica napus L. to calcium (Ca) enrichment in growth medium for reducing Cd toxicity stress by strengthening the photosynthesis organelles and their functionality was explored in this study. MATERIALS AND METHODS: B. napus seedlings of two cultivars (ZS 758 and ZS 72) were exposed to Cd toxicity at 500 µM in hydroponics, and it was ameliorated with Ca at 2.0 mM. The study included determinations and evaluations pertaining to physiological attributes of plant growth, chlorophyll, and photosynthesis. RESULTS AND DISCUSSION: Cadmium stress significantly depressed the seedling growth and reduced photosynthetic rate (Pn), stomatal conductivity (Gs), and transpiration rate (Tr). Further, Cd toxicity markedly decreased the electron transport rate of PSII, effective quantum yield of photochemical energy conversion in PSII [Y(II)], photosynthetic active radiation, coefficient of photochemical quenching (qP), and chlorophyll fluorescence decrease ratio (R(Fd)). Addition of Ca in Cd-stressed plants antagonized the toxicity effects on all the above-mentioned attributes. Calcium amendment also reversed the Cd stress-induced increase in intercellular CO(2) concentration (Ci) and non-photochemical quenching, and countered the Cd accumulation in seedlings. CONCLUSION: This study suggests that Ca(2+) in the proximity of plasma membrane is proficient in alleviating Cd toxicity by reducing the cell-surface negativity and competing for Cd(2+) ion influx. Consequently, both the plant growth and activity of diurnal photosynthetic system remain the least altered under Cd-provoked toxicity stress.

Insights into cadmium induced physiological and ultra-structural disorders in Juncus effusus L. and its remediation through exogenous citric acid.

This study appraised cadmium (Cd) toxicity stress in wetland plant Juncus effusus, and explored its potential for Cd phytoextraction through chelators (citric acid and EDTA). Cadmium altered morphological and physiological attributes of J. effusus as reflected by growth retardation. Citric acid in the presence of 100 µM Cd significantly countered Cd toxicity by improving plant growth. Elevated Cd concentrations reduced translocation factor that was increased under application of both chelators. Citric acid enhanced Cd accumulation, while EDTA reduced its uptake. Cadmium induced oxidative stress modified the antioxidative enzyme activity. Both levels of citric acid (2.5 and 5.0 mM) and lower EDTA concentration (2.5 mM) helped plants to overcome oxidative stress by enhancing their antioxidative enzyme activities. Cadmium damaged the root cells through cytoplasmic shrinkage and metal deposition. Citric acid restored structure and shape of root cells and eliminated plasmolysis; whereas, EDTA exhibited no positive effect on it. Shoot cells remained unaffected under Cd treatment alone or with citric acid except for chloroplast swelling. Only EDTA promoted starch accumulation in chloroplast reflecting its negative impact on cellular structure. It concludes that Cd and EDTA induce structural and morphological damage in J. effusus; while, citric acid ameliorates Cd toxicity stress.

Interactions of cadmium and aluminum toxicity in their effect on growth and physiological parameters in soybean.

The effect of Al and Cd on the growth, photosynthesis, and accumulation of Al, Cd and plant nutrients in two soybean genotypes were determined using hydroponic culture. There were six treatments: pH 6.5; pH 4.0; pH 6.5+1.0 micromol/L Cd; pH 4.0+1.0 micromol/L Cd; pH 4.0+150 micromol/L Al; pH 4.0+1.0 micromol/L Cd+150 micromol/L Al. The low pH (4.0) and Al treatments caused marked reduction in root length, shoot height, dry weight, chlorophyll content (SPAD value) and photosynthetic rate. Al-sensitive cv. Zhechun 2 accumulated comparatively more Al and Cd in plants than Al-tolerant cv. Liao 1. Compared with pH 6.5, pH 4.0 resulted in significant increase in Cd and Al concentration in plants. Combined application of Cd and Al enhanced their accumulation in roots, but caused a reduction in shoots. The concentrations of all 10 nutrients (P, K, Ca, Mg, Fe, Mn, Cu, Zn and B), except Mo were also increased when plants were exposed to pH lower than pH 6.5. Al addition caused a reduction in the concentration of most nutrients in plant roots and shoots; but K, Mn and Zn in roots were increased. Treatments with Cd alone or together with Al reduced the concentrations of all the plant nutrients in plants. Al-sensitive genotype Zhechun 2 has lower nutrient concentration than Al-tolerant genotype Liao 1. The current findings imply that Al and Cd are synergistic in their effect on plant growth, physiological traits and nutrient uptake.